For experienced users:
The formatters are being applied via -valueForKeyPath:
which means that anything in %() can be a complete KVC
keyPath. The second example (above) utilizes this feature and
guarantees, that the file extension (i.e. mp3) is
in lower case.

As you can see above, numbers can be formatted via a number
format… the separator character is #.

Sharing the iTunesFS filesystem via
Apache is pretty easy in itself,
and it gets even better if you share it via
WebDAV - this way, you can
mount the exported filesystem on Windows as a webfolder, map it to
a drive letter and so on.
Make sure to enable WebDAV in /etc/apache2/httpd.conf and
use something similar to the following rules somewhere in one of
the config files:

Regardless of this default, these files are always available. This means
that even though you can't see them, you can always write to them (i.e.
via scripts) or, in case of per playlist files, delete them to reset them
to their defaults.

(since version 1.2.0):
If you use the / character in a
formatter, this will create
additional folders for the components described by the formatter.

(since version 1.2.0):
Per playlist formatters are available now. In order to define them, you
first need to know the persistent ID of the playlist in question.
If a playlist has a persistent ID, then there's also a
PlaylistsTrackFormat.txt file. At the top of the file, the
name of the default is conveniently listed for you - something like
PlaylistsTrackFormat[id].

In addition to the format described above,
it's possible to create aliases. If you create a default, i.e.
PlaylistsTrackFormat[foobar] you can refer
to this default with this special syntax:
@foobar. I've already provided a
folders default to show/use.

If you want to know a playlist's persistent ID but don't want to
use format files, there's a new default which adds the persistent ID to
the name of each playlist which has a persistent ID assigned:

(since version 1.3.3):
A new folder Playlists (M3U) (name of the folder is localized) has
been introduced, containing
M3U files for all playlists in iTunes. The playlists
are not structured in the same way as the contents of the
Playlists folder as that's not possible with M3U. Instead, the
original iTunes order is presented. These playlists can be used as a
data source for i.e. a media server (I'm using this feature in conjunction
with MediaTomb which supports these M3U files out of the box).

(since version 1.3.3):
In order to provide playlists for 3rd party devices when copying the
(possibly restructured) contents of Playlists to another
destination, M3U playlists can now be generated on demand in all folders
which have content in them. These files are referenced relatively and
may thus be copied to any destination and work out of the box.

(since version 1.3.4):
M3U files are encoded using "Windows Latin 1" encoding by default.
This encoding is
suited for most western languages, but insufficient for the vast majority
of languages. Luckily, the file encoding can be switched to "UTF-8"
encoding, but that also implies a different file extension ("m3u8") for
the playlists to be used.

defaults write com.mulle-kybernetik.znek.iTunesFS UseM3U8 -bool YES

(since version 1.3.4):
If you know what you're doing, you can manually override the file extension
for M3U playlists with this user default